Performance of Multibeam Very High Throughput Satellite Systems Based on
FSO Feeder Links with HPA Nonlinearity
Abstract
Due to recent advances in laser satellite communications technology,
free-space optical (FSO) links are presented as an ideal alternative to
the conventional radio frequency (RF) feeder links of the geostationary
satellite for next generation very high throughput satellite (VHTS)
systems. In this paper, we investigate the performance of multibeam VHTS
systems that account for nonlinear high power amplifiers at the
transparent fixed gain satellite transponder. Specifically, we consider
the forward link of such systems, where the RF user link is assumed to
follow the shadowed Rician model and the FSO feeder link is modeled by
the Gamma-Gamma distribution in the presence of beam wander and pointing
errors where it operates under either the intensity modulation with
direct detection or the heterodyne detection. Moreover, zero-forcing
precoder is employed to mitigate the effect of inter-beam interference
caused by the aggressive frequency reuse in the user link. The
performance of the system under study is evaluated in terms of the
outage probability, the average bit-error rate (BER), and the ergodic
capacity that are derived in exact closed-forms in terms of the
bivariate Meijer’s G function. Simple asymptotic results for the outage
probability and the average BER are also obtained at high
signal-to-noise ratio.